本文主要給大家介紹了關(guān)于linux系統(tǒng)用戶管理與grep正則表達式的相關(guān)資料，文中通過示例代碼介紹的非常詳細，對大家學習或者使用linux系統(tǒng)具有一定的參考學習價值，希望能幫助到大家。
linux系統(tǒng)用戶管理與grep正則表達式
1、復制/etc/skel目錄為/home/tuser1，要求/home/tuser1及其內(nèi)部文件的屬組和其它用戶均沒有任何訪問權(quán)限。
[root@suywien?~]#?cp?-rpv?/etc/skel/?/home/tuser1/ ‘/etc/skel/'?->?‘/home/tuser1/' ‘/etc/skel/.mozilla'?->?‘/home/tuser1/.mozilla' ‘/etc/skel/.mozilla/extensions'?->?‘/home/tuser1/.mozilla/extensions' ‘/etc/skel/.mozilla/plugins'?->?‘/home/tuser1/.mozilla/plugins' ‘/etc/skel/.bash_logout'?->?‘/home/tuser1/.bash_logout' ‘/etc/skel/.bash_profile'?->?‘/home/tuser1/.bash_profile' ‘/etc/skel/.bashrc'?->?‘/home/tuser1/.bashrc' [root@suywien?~]#?useradd?tuser?-d?/home/tuser1/ useradd:?warning:?the?home?directory?already?exists. Not?copying?any?file?from?skel?directory?into?it. [root@suywien?~]#?chmod?-R?go-rwx?/home/tuser1/ [root@suywien?~]#?ll?-d?/home/tuser1/ drwx------?3?root?root?74?Feb?12?03:04?/home/tuser1/
2、編輯/etc/group文件，添加組hadoop。
[root@suywien?~]#?vim?/etc/group [root@suywien?~]#?tail?-1?/etc/group hadoop:x:1029
3、手動編輯/etc/passwd文件新增一行，添加用戶hadoop，其基本組ID為hadoop組的id號；其家目錄為/home/hadoop。
[root@suywien?~]#?vim?/etc/passwd [root@suywien?~]#?tail?-1?/etc/passwd hadoop:x:1029:1029::/home/hodoop/:/bin/bash
4、復制/etc/skel目錄為/home/hadoop，要求修改hadoop目錄的屬組和其它用戶沒有任何訪問權(quán)限。
[root@suywien?~]#?cp?-fpv?/etc/skel/?/home/hadoop cp:?omitting?directory?‘/etc/skel/' [root@suywien?~]#?cp?-fpvR?/etc/skel/?/home/hadoop ‘/etc/skel/'?->?‘/home/hadoop' ‘/etc/skel/.mozilla'?->?‘/home/hadoop/.mozilla' ‘/etc/skel/.mozilla/extensions'?->?‘/home/hadoop/.mozilla/extensions' ‘/etc/skel/.mozilla/plugins'?->?‘/home/hadoop/.mozilla/plugins' ‘/etc/skel/.bash_logout'?->?‘/home/hadoop/.bash_logout' ‘/etc/skel/.bash_profile'?->?‘/home/hadoop/.bash_profile' ‘/etc/skel/.bashrc'?->?‘/home/hadoop/.bashrc' [root@suywien?~]#?chmod?go-rwx?/home/hadoop/ [root@suywien?~]#?ls?-ld?/home/hadoop/ drwx------?3?root?root?74?Feb?12?03:04?/home/hadoop/
5、修改/home/hadoop目錄及其內(nèi)部所有文件的屬主為hadoop，屬組為hadoop。
[root@suywien?~]#?chown?-R?hadoop:hadoop?/home/hadoop/ [root@suywien?~]#?ll?-al?/home/hadoop/ total?16 drwx------?3?hadoop?hadoop?74?Feb?12?03:04?. drwxr-xr-x.?10?root?root?4096?Mar?25?10:14?.. -rw-r--r--?1?hadoop?hadoop?18?Nov?20?2015?.bash_logout -rw-r--r--?1?hadoop?hadoop?193?Nov?20?2015?.bash_profile -rw-r--r--?1?hadoop?hadoop?231?Nov?20?2015?.bashrc drwxr-xr-x?4?hadoop?hadoop?37?Feb?12?03:03?.mozilla
6、顯示/proc/meminfo文件中以大寫或小寫S開頭的行；用兩種方式；
[root@suywien?~]#?grep?^[S,s]?/proc/meminfo? ?SwapCached:???0?kB ?SwapTotal:??2097148?kB ?SwapFree:??2097148?kB ?Shmem:????9100?kB ?Slab:????89476?kB ?SReclaimable:??53176?kB ?SUnreclaim:??36300?kB
[root@suywien?~]#?grep?-i?"^s"?/proc/meminfo? ?SwapCached:???0?kB ?SwapTotal:??2097148?kB ?SwapFree:??2097148?kB ?Shmem:????9100?kB
7、顯示/etc/passwd文件中其默認shell為非/sbin/nologin的用戶；
[root@suywien?~]#?grep?/sbin/nologin$?/etc/passwd bin:x:1:1:bin:/bin:/sbin/nologin daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin mail:x:8:12:mail:/var/spool/mail:/sbin/nologin ......
8、顯示/etc/passwd文件中其默認shell為/bin/bash的用戶；
[root@suywien?~]#?grep?/bin/bash?/etc/passwd root:x:0:0:root:/root:/bin/bash roo:x:1000:1000:root:/home/roo:/bin/bash gentoo:x:4001:4001::/home/gentoo:/bin/bash mageia:x:1100:1100::/home/linux:/bin/bash tuser:x:4003:4003::/home/tuser1/:/bin/bash hadoop:x:1029:1029::/home/hodoop/:/bin/bash
9、找出/etc/passwd文件中的一位數(shù)或兩位數(shù)；
[root@suywien?~]#?grep?""?/etc/passwd mail:x:8:12:mail:/var/spool/mail:/sbin/nologin operator:x:11:0:operator:/root:/sbin/nologin games:x:12:100:games:/usr/games:/sbin/nologin ftp:x:14:50:FTP?User:/var/ftp:/sbin/nologin ......
10、顯示/boot/grub/grub.conf中以至少一個空白字符開頭的行；
[root@suywien?~]#?grep?"^[[:space:]]+"?/boot/grub2/grub.cfg? ?load_env ?set?default="${next_entry}" ?set?next_entry= ?save_env?next_entry ?set?boot_once=true ?......
11、顯示/etc/rc.d/rc.sysinit文件中以#開頭，后面跟至少一個空白字符，而后又有至少一個非空白字符的行；
[root@suywien?~]#?grep?"^#[[:space:]]+[^[:space:]]+"?/etc/rc.d/rc.local? #?THIS?FILE?IS?ADDED?FOR?COMPATIBILITY?PURPOSES #?It?is?highly?advisable?to?create?own?systemd?services?or?udev?rules #?to?run?scripts?during?boot?instead?of?using?this?file. #?In?contrast?to?previous?versions?due?to?parallel?execution?during?boot #?this?script?will?NOT?be?run?after?all?other?services. #?Please?note?that?you?must?run?'chmod?+x?/etc/rc.d/rc.local'?to?ensure #?that?this?script?will?be?executed?during?boot.
12、打出netstat -tan命令執(zhí)行結(jié)果中以‘LISTEN’，后或跟空白字符結(jié)尾的行；
[root@suywien?~]#?netstat?-tan?|?grep?"LISTEN[[:space:]]*$" tcp??0??0?192.168.122.1:53??0.0.0.0:*????LISTEN?? tcp??0??0?0.0.0.0:22????0.0.0.0:*????LISTEN?? tcp??0??0?127.0.0.1:631???0.0.0.0:*????LISTEN?? tcp??0??0?127.0.0.1:25???0.0.0.0:*????LISTEN?? tcp6??0??0?:::22?????:::*?????LISTEN?? tcp6??0??0?::1:631?????:::*?????LISTEN?? tcp6??0??0?::1:25?????:::*?????LISTEN
13、添加用戶bash, testbash, basher, nologin (此一個用戶的shell為/sbin/nologin)，而后找出當前系統(tǒng)上其用戶名和默認shell相同的用戶的信息；
[root@suywien?~]#?useradd?bash [root@suywien?~]#?useradd?basher [root@suywien?~]#?useradd?-s?/sbin/nologin?nologin [root@suywien?~]#?grep?-E?"^([^:]+>).*1$"?/etc/passwd sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt bash:x:4004:4004::/home/bash:/bin/bash nologin:x:4006:4006::/home/nologin:/sbin/nologin
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